Ventilation fan



FIG. 1 is a perspective view of a ventilation fan showing my new design;

FIG. 2 is another perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a right view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is bottom plan view thereof.

The broken lines showing of the ventilation fan are for the purpose ofillustrating article and form no part of the claimed design.

CLAIM The ornamental design for a ventilation fan, as shown anddescribed.